ML570 (Xeon 700mHz, 2G ram) hangs searching SCSI devices on booting

Hello All.

Well, I have a Proliant ML570 Xeon 700Mhz, 2G RAM, four disks 18G 10K. The server hangs on booting, when searches for SCSI drives. This is when the onboard SCSI controller searches for SCSI devices. No matter what is attached to the onboard controller, after detecting it, stays searching another devices. if no device is attached, hangs searching anyway. I have a spare ML570 from which taking parts, and I have replaced cables, and also the onboard SCSI controller (it is a board inserted in a slot, that provides serial and parallel ports, mouse, keyboard, video and SCSI connectors). One or more times booted normally, but the same problem arises later.